MicroRNA-23a promotes colorectal cancer cell survival by targeting PDK4

Comparison of the diagnostic value of various microRNAs in blood for colorectal cancer: a systematic review and network meta-analysis

BACKGROUND

Despite the existence of numerous studies investigating the diagnostic potential of blood microRNAs for colorectal cancer, the microRNAs under consideration vary widely, and comparative analysis of their diagnostic value is lacking. Consequently, this systematic review aims to identify the most effective microRNA blood tumor markers to enhance clinical decision-making in colorectal cancer screening.

METHOD

A comprehensive search of databases, including PubMed, Embase, Web of Science, Scopus, and Cochrane, was conducted to identify case‒control or cohort studies that examined the diagnostic value of peripheral blood microRNAs in colorectal cancer. Studies were included if they provided sensitivity and specificity data, were published in English and were available between January 1, 2000, and February 10, 2023. The Critical Appraisal Skills Programme (CASP) checklist was employed for quality assessment. A Bayesian network meta-analysis was performed to estimate combined risk ratios (RRs) and 95% confidence intervals (CIs), with results presented via rankograms. This study is registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), 202,380,092.

RESULTS

From an initial pool of 2254 records, 79 met the inclusion criteria, encompassing a total of 90 microRNAs. The seven most frequently studied microRNAs (43 records) were selected for inclusion, all of which demonstrated moderate to high quality. miR-23, miR-92, and miR-21 exhibited the highest sensitivity and accuracy, outperforming traditional tumor markers CA19-9 and CEA in terms of RR values and 95% CI for both sensitivity and accuracy. With the exception of miR-17, no significant difference was observed between each microRNA and CA19-9 and CEA in terms of specificity.

CONCLUSIONS

Among the most extensively researched blood microRNAs, miR-23, miR-92, and miR-21 demonstrated superior diagnostic value for colorectal cancer due to their exceptional sensitivity and accuracy. This systematic review and network meta-analysis may serve as a valuable reference for the clinical selection of microRNAs as tumor biomarkers.

Prognostic value of RNA methylation-related genes in gastric adenocarcinoma based on bioinformatics

Background

Gastric cancer (GC) is a malignant tumor that originates from the epithelium of the gastric mucosa and has a poor prognosis. Stomach adenocarcinoma (STAD) covers 95% of total gastric cancer. This study aimed to identify the prognostic value of RNA methylation-related genes in gastric cancer.

Methods

In this study, The Cancer Genome Atlas (TCGA)-STAD and GSE84426 cohorts were downloaded from public databases. Patients were classified by consistent cluster analysis based on prognosis-related differentially expressed RNA methylation genes Prognostic genes were obtained by differential expression, univariate Cox and least absolute shrinkage and selection operator (LASSO) analyses. The prognostic model was established and validated in the training set, test set and validation set respectively. Independent prognostic analysis was implemented. Finally, the expression of prognostic genes was affirmed by reverse transcription quantitative PCR (RT-qPCR).

Results

In total, four prognostic genes (ACTA2, SAPCD2, PDK4 and APOD) related to RNA methylation were identified and enrolled into the risk signature. The STAD patients were divided into high- and low-risk groups based on the medium value of the risk score, and patients in the high-risk group had a poor prognosis. In addition, the RNA methylation-relevant risk signature was validated in the test and validation sets, and was authenticated as a reliable independent prognostic predictor. The nomogram was constructed based on the independent predictors to predict the 1/3/5-year survival probability of STAD patients. The gene set enrichment analysis (GSEA) result suggested that the poor prognosis in the high-risk subgroup may be related to immune-related pathways. Finally, the experimental results indicated that the expression trends of RNA methylation-relevant prognostic genes in gastric cancer cells were in agreement with the result of bioinformatics.

Conclusion

Our study established a novel RNA methylation-related risk signature for STAD, which was of considerable significance for improving prognosis of STAD patients and offering theoretical support for clinical therapy.

Serum miR-23 and miR-150 Profiles as Biomarkers for Predicting Recurrence following Surgical Intervention in Colorectal Cancer Patients

Background

MicroRNAs (miRNAs) play pivotal roles in post-transcriptional regulation of gene expression and have emerged as crucial regulators in cancer development, progression, and metastasis. This study aimed to assess the expression profiles of miR-23, miR-223, miR-1246, and miR-150 in serum samples obtained from colorectal cancer (CRC) patients before and three months after surgery, in comparison to a healthy control group, to explore their biomarker potential.

Methods

A total of 50 blood samples were collected from patients with CRC (pre- and post-surgery), along with 50 samples from healthy controls. The relative expression levels of miR-23, miR-223, miR-1246, and miR-150 in the serum were quantified using quantitative real-time PCR.

Results

Our findings revealed upregulated expression levels of miR-23, miR-1246, and miR-223, while miR-150 exhibited significant downregulation in the serum of CRC subjects compared to healthy controls. Receiver operating characteristic (ROC) analysis indicated that miR-23 and miR-150 could distinguish CRC cases from controls with relatively high accuracy. Moreover, three months post-surgery, miR-23, miR-1246, and miR-223 serum levels were downregulated, and miR-150 was significantly upregulated. However, no significant correlations were observed between serum levels of the studied genes and the clinical features of our patients.

Conclusions

The serum levels of miR-23 and miR-150 hold promise as potential biomarkers for the diagnosis and prognosis of CRC.

High glucose promotes benign prostatic hyperplasia by downregulating PDK4 expression

As men age, a growing number develop benign prostatic hyperplasia (BPH). According to previous research, diabetes may be a risk factor. Pyruvate dehydrogenase kinase 4 (PDK4) is closely related to glucose metabolism and plays a role in the onset and progression of numerous illnesses. This study aimed to determine the direct effects of high glucose environment on prostate epithelial cells, in particular by altering PDK4 expression levels. In this investigation, normal prostatic epithelial cells (RWPE-1) and human benign prostatic hyperplasia epithelial cells (BPH-1) were treated with 50 mM glucose to show the alteration of high glucose in prostate cells. PDK4-target siRNA, PDK4-expression plasmid were used to investigate the effects of PDK4. Rosiglitazone (RG), a PPARγ agonist, with the potential to up-regulate PDK4 expression was also used for treating prostate cells. The expression of PDK4 in human prostate samples was also analyzed. The effects of high glucose therapy on BPH-1 and RWPE-1 cells were demonstrated to enhance proliferation, epithelial-mesenchymal transition (EMT), suppress apoptosis, and down-regulate PDK4 expression. Additionally, diabetes-related BPH patients had reduced PDK4 expression. Following the application of PDK4-target siRNA, a comparable outcome was seen. The PDK4-expression plasmid therapy, however, produced the opposite results. RG with the ability to elevate PDK4 expression might be used to treat BPH. Changes in the metabolism of lipids and glucose may be the cause of these consequences. These findings showed that high glucose treatment might facilitate BPH development, and may be related to the down-regulation of PDK4. PDK4 might be a potential therapeutic target of BPH.

TNFα increases the degradation of pyruvate dehydrogenase kinase 4 by the Lon protease to support proinflammatory genes

The endothelium is a major target of the proinflammatory cytokine, tumor necrosis factor alpha (TNFα). Exposure of endothelial cells (EC) to proinflammatory stimuli leads to an increase in mitochondrial metabolism; however, the function and regulation of elevated mitochondrial metabolism in EC in response to proinflammatory cytokines remain unclear. Studies using high-resolution metabolomics and 13C-glucose and 13C-glutamine labeling flux techniques showed that pyruvate dehydrogenase activity (PDH) and oxidative tricarboxylic acid cycle (TCA) flux are elevated in human umbilical vein ECs in response to overnight (16 h) treatment with TNFα (10 ng/mL). Mechanistic studies indicated that TNFα mediated these metabolic changes via mitochondrial-specific protein degradation of pyruvate dehydrogenase kinase 4 (PDK4, inhibitor of PDH) by the Lon protease via an NF-κB-dependent mechanism. Using RNA sequencing following siRNA-mediated knockdown of the catalytically active subunit of PDH, PDHE1α (PDHA1 gene), we show that PDH flux controls the transcription of approximately one-third of the genes that are up-regulated by TNFα stimulation. Notably, TNFα-induced PDH flux regulates a unique signature of proinflammatory mediators (cytokines and chemokines) but not inducible adhesion molecules. Metabolomics and ChIP sequencing for acetylated modification on lysine 27 of histone 3 (H3K27ac) showed that TNFα-induced PDH flux promotes histone acetylation of specific gene loci via citrate accumulation and ATP-citrate lyase-mediated generation of acetyl CoA. Together, these results uncover a mechanism by which TNFα signaling increases oxidative TCA flux of glucose to support TNFα-induced gene transcription through extramitochondrial acetyl CoA generation and histone acetylation.

Decoding the regulatory roles of non-coding RNAs in cellular metabolism and disease

Non-coding RNAs, including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are being studied extensively in a variety of fields. Their roles in metabolism have received increasing attention in recent years but are not yet clear. The regulation of glucose, fatty acid, and amino acid metabolism is an imperative physiological process that occurs in living organisms and takes part in cancer and cardiovascular diseases. Here, we summarize the important roles played by non-coding RNAs in glucose metabolism, fatty acid metabolism, and amino acid metabolism, as well as the mechanisms involved. We also summarize the therapeutic advances for non-coding RNAs in diseases such as obesity, cardiovascular disease, and some metabolic diseases. Overall, non-coding RNAs are indispensable factors in metabolism and have a significant role in the three major metabolisms, which may be exploited as therapeutic targets in the future.

Mitochondrial remodeling in colorectal cancer initiation, progression, metastasis, and therapy: A review

Colorectal cancer (CRC) is a major health concern with multifactorial pathophysiology representing intense therapeutic challenges. It is well known that deregulation of spatiotemporally-controlled signaling pathways and their metabolic reprogramming effects play a pivotal role in the development and progression of CRC. As such, the mitochondrial role in CRC initiation gained a lot of attention recently, as it is considered the powerhouse that regulates the bioenergetics in CRC. In addition, the crosstalk between microRNAs (miRNAs) and mitochondrial dysfunction has become a newfangled passion for deciphering CRC molecular mechanisms. This review sheds light on the relationship between different signaling pathways involved in metabolic reprogramming and their therapeutic targets, alterations in mitochondrial DNA content, mitochondrial biogenesis, and mitophagy, and the role of polymorphisms in mitochondrial genes as well as miRNAs regulating mitochondrial proteins in CRC initiation, progression, metastasis, and resistance to various therapies.

Overexpression of miRNA 26a and 26b with MMP-9 are valuable diagnostic biomarkers for colorectal cancer patients

Background: The key role of miRNA expression in incidence and progression of colorectal cancer (CLC) have been developed over the last decade. Materials & methods: A total of 153 subjects were enrolled into two phases: 14 selected miRNAs were first evaluated in 50 subjects, then miR-26a and miR-26b relative expression were further evaluated in 103 subjects and their target protein MMP-9 was measured. Results: miR-26a and -26b showed highly significant overexpression. Both miR-26a and -26b (p < 0.001) had high diagnostic efficacy for CRC. There was a significant increase in serum MMP-9 protein in CRC patients with positive correlation with miR-26a and -26b expression levels (p < 0.001). Conclusion: miRNA 26a and 26b with MMP-9 can be used as diagnostic biomarker for CRC patients.

MEIS1 Is a Common Transcription Repressor of the miR-23a and NORHA Axis in Granulosa Cells

MicroRNA-23a (miR-23a) is an endogenous small activating RNA (saRNA) involved in ovarian granulosa cell (GC) apoptosis and sow fertility by activating lncRNA NORHA transcription. Here, we reported that both miR-23a and NORHA were repressed by a common transcription factor MEIS1, which forms a small network regulating sow GC apoptosis. We characterized the pig miR-23a core promoter, and the putative binding sites of 26 common transcription factors were detected in the core promoters of both miR-23a and NORHA. Of them, transcription factor MEIS1 expression was the highest in the ovary, and widely distributed in various ovarian cells, including GCs. Functionally, MEIS1 is involved in follicular atresia by inhibiting GC apoptosis. Luciferase reporter and ChIP assays showed that transcription factor MEIS1 represses the transcription activity of miR-23a and NORHA through direct binding to their core promoters. Furthermore, MEIS1 represses miR-23a and NORHA expression in GCs. Additionally, MEIS1 inhibits the expression of FoxO1, a downstream of the miR-23a/NORHA axis, and GC apoptosis by repressing the miR-23a/NORHA axis. Overall, our findings point to MEIS1 as a common transcription repressor of miR-23a and NORHA, and develop the miR-23a/NORHA axis into a small regulatory network regulating GC apoptosis and female fertility.

Biological implications and clinical potential of invasion and migration related miRNAs in glioma

Gliomas are the most common primary malignant brain tumors and are highly aggressive. Invasion and migration are the main causes of poor prognosis and treatment resistance in gliomas. As migration and invasion occur, patient survival and prognosis decline dramatically. MicroRNAs (miRNAs) are small, non-coding 21–23 nucleotides involved in regulating the malignant phenotype of gliomas, including migration and invasion. Numerous studies have demonstrated the mechanism and function of some miRNAs in glioma migration and invasion. However, the biological and clinical significance (including diagnosis, prognosis, and targeted therapy) of glioma migration and invasion-related miRNAs have not been systematically discussed. This paper reviews the progress of miRNAs-mediated migration and invasion studies in glioma and discusses the clinical value of migration and invasion-related miRNAs as potential biomarkers or targeted therapies for glioma. In addition, these findings are expected to translate into future directions and challenges for clinical applications. Although many biomarkers and their biological roles in glioma invasion and migration have been identified, none have been specific so far, and further exploration of clinical treatment is still in progress; therefore, we aimed to further identify specific markers that may guide clinical treatment and improve the quality of patient survival.

MicroRNA-7 regulates insulin signaling pathway by targeting IRS1, IRS2, and RAF1 genes in gestational diabetes mellitus

BACKGROUND

Small non-coding micro RNAs (miRNAs) are indicated in various metabolic processes and play a critical role in disease pathology, including gestational diabetes mellitus (GDM).

OBJECTIVE

The purpose of this study was to examine the altered expression of miRNAs and their target genes in placental tissue (PL), cord blood (CB), and maternal blood (MB) of matched non-glucose tolerant (NGT) and GDM mother.

METHODS

In a case-control study, micro-RNA was quantified from forty-five serum (MB n = 15, CB n = 15, and PL n = 15) and matched placental tissue using stem-loop RT-qPCR followed by target prediction, network construction and functional and pathways enrichment analysis. Further, target genes were verified in-vitro through transfection and RT-qPCR.

RESULTS

Five miRNAs, namely hsa-let 7a-5P, hsa-miR7-5P, hsa-miR9-5P, hsa-miR18a-5P, and hsa-miR23a-3P were significantly over-expressed (p < 0.05) in all three samples namely PL, CB, and MB of GDM patients. However, the sample-wise comparison reveals higher expression of miRNA 7 in MB while lowest in CB than control. Furthermore, a comparison of fold change expression of target genes discloses a lower expression of IRS1, IRS2, and RAF1 in MB while comparatively higher expression of NRAS in MB and CB. In-vitro validation reveals lower expression of IRS1/2 and RAF1 in response to overexpression of miR-7 and vice-versa. Thus it is evident that increased miRNA7 expression causes down-regulation of its target genes IRS1, IRS2, and RAF1 in GDM mother compared to control. Further, target prediction, pathway enrichment, and hormone analysis (significantly higher FSH & LH in MB of GDM compared to NGT) revealed the insulin signaling, inflammatory and GnRH signaling as major pathways regulated by miRNA7.

CONCLUSIONS

Thus, an elevated level of miRNA7 may be associated with the progression of GDM by altering the multiple pathways like insulin, GnRH, and inflammatory signaling pathways via targeting IRS1, IRS2, and RAF1, implicating a new therapeutic target for GDM.

The Role of MiRNA in Cancer: Pathogenesis, Diagnosis, and Treatment

Cancer is also determined by the alterations of oncogenes and tumor suppressor genes. These gene expressions can be regulated by microRNAs (miRNA). At this point, researchers focus on addressing two main questions: "How are oncogenes and/or tumor suppressor genes regulated by miRNAs?" and "Which other mechanisms in cancer cells are regulated by miRNAs?" In this work we focus on gathering the publications answering these questions. The expression of miRNAs is affected by amplification, deletion or mutation. These processes are controlled by oncogenes and tumor suppressor genes, which regulate different mechanisms of cancer initiation and progression including cell proliferation, cell growth, apoptosis, DNA repair, invasion, angiogenesis, metastasis, drug resistance, metabolic regulation, and immune response regulation in cancer cells. In addition, profiling of miRNA is an important step in developing a new therapeutic approach for cancer.

The Circular RNA circXPO1 Promotes Tumor Growth via Sponging MicroRNA-23a in Prostate Carcinoma

It has been shown that circular RNA XPO1 (circXPO1) is involved in cancer (e.g., lung adenocarcinoma and osteosarcoma) progression by sponging microRNAs. Nevertheless, the role of circXPO1 and its interaction with microRNAs in prostate cancer remains unknown. In this study, the results of quantitative real-time PCR showed that circXPO1 levels were dramatically increased in human prostate cancer tissue and cell lines compared with those in normal tissue and cell line. Furthermore, cell proliferation, colony formation, and cell invasion assays showed that circXPO1 promoted the malignant behavior of pancreatic cells in vitro. Mechanistically, bioinformatics prediction, a dual-luciferase reporter assay, and pull-down assay suggested that circXPO1 physically targets miR-23a and negatively regulates its expression in pancreatic cancer cells. miR-23a mimics and inhibitors effectively reversed the effects of circXPO1 on the malignant behavior of prostate cancer cells in vitro. Consistent results were observed in the xenograft tumor model. In conclusion, circXPO1 promotes prostate cancer progression via targeting miR-23a, thus suggesting the circXPO1/miR-23a axis can be used as a potential therapeutic target for prostate cancer treatment.

Reversing tozasertib resistance in glioma through inhibition of pyruvate dehydrogenase kinases

Acquired resistance to conventional chemotherapeutic agents limits their effectiveness and can cause cancer treatment to fail. Because enzymes in the aurora kinase family are vital regulators of several mitotic events, we reasoned that targeting these kinases with tozasertib, a pan‐aurora kinase inhibitor, would not only cause cytokinesis defects, but also induce cell death in high‐grade pediatric and adult glioma cell lines. We found that tozasertib induced cell cycle arrest, increased mitochondrial permeability and reactive oxygen species generation, inhibited cell growth and migration, and promoted cellular senescence and pro‐apoptotic activity. However, sustained exposure to tozasertib at clinically relevant concentrations conferred resistance, which led us to examine the mechanistic basis for the emergence of drug resistance. RNA‐sequence analysis revealed a significant upregulation of the gene encoding pyruvate dehydrogenase kinase isoenzyme 4 (PDK4), a pyruvate dehydrogenase (PDH) inhibitory kinase that plays a crucial role in the control of metabolic flexibility under various physiological conditions. Upregulation of PDK1, PDK2, PDK3, or PDK4 protein levels was positively correlated with tozasertib‐induced resistance through inhibition of PDH activity. Tozasertib‐resistant cells exhibited increased mitochondrial mass as measured by 10‐N‐nonyl‐Acridine Orange. Inhibition of PDK with dichloroacetate resulted in increased mitochondrial permeability and cell death in tozasertib‐resistant glioma cell lines. Based on these results, we believe that PDK is a selective target for the tozasertib resistance phenotype and should be considered for further preclinical evaluations.

Targeting pyruvate dehydrogenase kinase signaling in the development of effective cancer therapy

Pyruvate is irreversibly decarboxylated to acetyl coenzyme A by mitochondrial pyruvate dehydrogenase complex (PDC). Decarboxylation of pyruvate is considered a crucial step in cell metabolism and energetics. The cancer cells prefer aerobic glycolysis rather than mitochondrial oxidation of pyruvate. This attribute of cancer cells allows them to sustain under indefinite proliferation and growth. Pyruvate dehydrogenase kinases (PDKs) play critical roles in many diseases because they regulate PDC activity. Recent findings suggest an altered metabolism of cancer cells is associated with impaired mitochondrial function due to PDC inhibition. PDKs inhibit the PDC activity via phosphorylation of the E1a subunit and subsequently cause a glycolytic shift. Thus, inhibition of PDK is an attractive strategy in anticancer therapy. This review highlights that PDC/PDK axis could be implicated in cancer's therapeutic management by developing potential small-molecule PDK inhibitors. In recent years, a dramatic increase in the targeting of the PDC/PDK axis for cancer treatment gained an attention from the scientific community. We further discuss breakthrough findings in the PDC-PDK axis. In addition, structural features, functional significance, mechanism of activation, involvement in various human pathologies, and expression of different forms of PDKs (PDK1-4) in different types of cancers are discussed in detail. We further emphasized the gene expression profiling of PDKs in cancer patients to prognosis and therapeutic manifestations. Additionally, inhibition of the PDK/PDC axis by small molecule inhibitors and natural compounds at different clinical evaluation stages has also been discussed comprehensively.

MiR-122-5p suppresses neuropathic pain development by targeting PDK4

The complex pathogenesis and limited efficacy of available treatment make neuropathic pain difficult for long periods of time. Several findings suggested the regulatory role of microRNA in the development of neuropathic pain. This study aims to investigate the functional role of miR-122-5p in the development of neuropathic pain. Down-regulation of miR-122-5p was observed in spinal cords of rats with neuropathic pain. We also found that overexpressing miR-122-5p by intrathecal injection of miR-122-5p lentivirus in a mouse model of chronic sciatic nerve injury (CCI) prevented neuropathic pain behavior. In HEK-293 T cells, luciferase activity was significantly decreased in the transfection group with mimic-miR-122-5p in wild-type PDK4 reporter, compared with mutant PDK4 reporter. Increased PDK4 expression was also observed during the progression of neuropathic pain. Intrathecal injection of both mimic-miR-122-5p and shPDK4 in CCI mice downregulated PDK4 expression to a lower level when compared with injected with shPDK4. In CCI mice, transfection of shPDK4 suppressed mechanical allodynia and thermal hyperalgesia, while co-transfection of shPDK4 and LV-miR-122-5p resulted in stronger levels of mechanical allodynia and thermal hyperalgesia inhibition. Taken together, the data suggest that miR-122-5p inhibits PDK4 expression, attenuating neuropathic pain. This result suggests the potential role of miR-122-5p acting as a target for the treatment of neuropathic pain.

Circulating miRNA as Biomarkers for Colorectal Cancer Diagnosis and Liver Metastasis

Colorectal cancer (CRC) is the second leading cause of cancer deaths worldwide. Stage IV CRC patients have poor prognosis with a five-year survival rate of 14%. Liver metastasis is the main cause of mortality in CRC patients. Since current screening tests have several drawbacks, effective stable non-invasive biomarkers such as microRNA (miRNA) are needed. We aim to investigate the expression of miRNA (miR-21, miR-19a, miR-23a, miR-29a, miR-145, miR-203, miR-155, miR-210, miR-31, and miR-345) in the plasma of 62 Lebanese Stage IV CRC patients and 44 healthy subjects using RT-qPCR, as well as to evaluate their potential for diagnosis of advanced CRC and its liver metastasis using the Receiver Operating Characteristics (ROC) curve. miR-21, miR-145, miR-203, miR-155, miR-210, miR-31, and miR-345 were significantly upregulated in the plasma of surgery naïve CRC patients when compared to healthy individuals. We identified two panels of miRNA that could be used for diagnosis of Stage IV CRC (miR-21 and miR-210) with an area under the curve (AUC) of 0.731 and diagnostic accuracy of 69% and liver metastasis (miR-210 and miR-203) with an AUC = 0.833 and diagnostic accuracy of 72%. Panels of specific circulating miRNA, which require further validation, could be potential non-invasive diagnostic biomarkers for CRC and liver metastasis.

Dissecting miRNA signature in colorectal cancer progression and metastasis

Colorectal cancer (CRC) is the third most common cancer and leading cause of cancer related deaths worldwide. Despite recent advancements in surgical and molecular targeted therapies that improved the therapeutic efficacy in CRC, the 5 years survival rate of CRC patients still remains frustratingly poor. Accumulated evidences indicate that microRNAs (miRNAs) play a crucial role in the progression and metastasis of CRC. Dysregulated miRNAs are closely associated with cancerous phenotypes (e.g. enhanced proliferative and invasive ability, evasion of apoptosis, cell cycle aberration, and promotion of angiogenesis) by regulating their target genes. In this review, we provide an updated overview of tumor suppressive and oncogenic miRNAs, circulatory miRNAs, and the possible causes of dysregulated miRNAs in CRC. In addition, we discuss the important functions of miRNAs in drug resistance of CRC.

Differential Expression of miR-21, miR-23a, and miR-27a, and Their Diagnostic Significance in Egyptian Colorectal Cancer Patients

Background: Colorectal cancer (CRC) rates are affected by genetics, ethnicity, and environmental factors; it is considered one of the most aggressive human malignancies with high mortality and morbidity rates worldwide due, in part, to its asymptomatic nature during the early stages of disease. Objective: Owing to the impact of microRNA (miRNA) dysregulation on CRC development and progression, this study was conducted to explore the expression levels of mir-21, -23a, and -27a in the sera and tissues of Egyptian CRC patients and to evaluate their diagnostic efficacy based on circulating levels. Methods: In the test phase, the relative expression levels of the studied miRNAs were evaluated in the sera of 70 participants (35 CRC patients and 35 healthy controls) using quantitative real-time-polymerase chain reaction and to verify their diagnostic value. The exploratory phase was designed to validate the tumor-derived trait by comparing the miRNA levels in the cancerous and adjacent noncancerous tissues. Results: The relative expression levels of the studied miRNAs were significantly upregulated in both serum and tumor tissues of the patients compared to their corresponding controls. In addition, significant positive correlations were found between the relative expression levels of the studied miRNAs in serum samples and their levels in the matched CRC tissues. The serum expression levels of mir-21 and -23a were more predictive of CRC than mir-27a. Conclusion: Circulating mir-21, -23a, and -27a expression levels appear to be valuable diagnostic biomarkers for CRC, especially when combined.

MicroRNA, Diabetes Mellitus and Colorectal Cancer

Diabetes mellitus (DM) is an endocrinological disorder that is due to either the pancreas not producing enough insulin, or the body does not respond appropriately to insulin. There are many complications of DM such as retinopathy, nephropathy, and peripheral neuropathy. In addition to these complications, DM was reported to be associated with different cancers. In this review, we discuss the association between DM and colorectal cancer (CRC). CRC is the third most commonly diagnosed cancer worldwide that mostly affects older people, however, its incidence and mortality are rising among young people. We discuss the relationship between DM and CRC based on their common microRNA (miRNA) biomarkers. miRNAs are non-coding RNAs playing important functions in cell differentiation, development, regulation of cell cycle, and apoptosis. miRNAs can inhibit cell proliferation and induce apoptosis in CRC cells. miRNAs also can improve glucose tolerance and insulin sensitivity. Therefore, investigating the common miRNA biomarkers of both DM and CRC can shed a light on how these two diseases are correlated and more understanding of the link between these two diseases can help the prevention of both DM and CRC.

Insights into the Role of microRNAs in Colorectal Cancer (CRC) Metabolism

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers, with a high mortality rate globally. The pathophysiology of CRC is mainly initiated by alteration in gene expression, leading to dysregulation in multiple signalling pathways and cellular processes. Metabolic reprogramming is one of the important cancer hallmarks in CRC, which involves the adaptive changes in tumour cell metabolism to sustain the high energy requirements for rapid cell proliferation. There are several mechanisms in the metabolic reprogramming of cancer cells, such as aerobic glycolysis, oxidative phosphorylation, lactate and fatty acids metabolism. MicroRNAs (miRNAs) are a class of non-coding RNAs that are responsible for post-transcriptional regulation of gene expression. Differential expression of miRNAs has been shown to play an important role in different aspects of tumorigenesis, such as proliferation, apoptosis, and drug resistance, as well as metabolic reprogramming. Increasing evidence also reports that miRNAs could function as potential regulators of metabolic reprogramming in CRC cells. This review provides an insight into the role of different miRNAs in regulating the metabolism of CRC cells as well as to discuss the potential role of miRNAs as biomarkers or therapeutic targets in CRC tumour metabolism.

Toosendanin induces apoptosis of MKN‑45 human gastric cancer cells partly through miR‑23a‑3p‑mediated downregulation of BCL2

Toosendanin (TSN) is a tetracyclic triterpenoid extracted from Melia toosendan Sieb, et Zucc, which primarily grows in specific areas of China. Although toosendanin (TSN) exerts antitumoral effects on various human cancer cells, its influence on gastric cancer (GC) is remains to be elucidated. MicroRNAs (miRNAs/miRs) serve crucial roles in apoptosis and proliferation of cancer cells. miR-23a-3p has been shown to be associated with human GC; however, the specific function of miR-23a-3p in GC remains unclear. Therefore, the present study aimed to elucidate the role of miR-23a-3p in the regulation of GC cell proliferation and apoptosis induced in vitro by TSN treatment. Subsequently, apoptosis-related genes expression levels were quantified by reverse transcription-quantitative PCR and western blot analysis, respectively, and the target relationship between miR-23a-3p and BCL2 was determined by luciferase reporter gene analysis. Additionally, cell proliferation and apoptosis experiments were carried out. The results indicated that TSN inhibited proliferation and induced apoptosis in MKN-45 cells. Moreover, it upregulated the expression of miR-23a-3p. B-cell lymphoma-2 (BCL2) was identified as a potential target gene of miR-23a-3p, which was demonstrated to bind to the 3′-untranslated region of BCL2 mRNA, as detected by the luciferase reporter assay. Further studies revealed that BCL2 expression was downregulated following overexpression of miR-23a-3p. In addition, the overexpression of the miR-23a-3p inhibited proliferation, induced G₁ arrest and increased apoptosis in MKN-45 cells. The results of the present study demonstrated that miR-23a-3p inhibited proliferation and induced apoptosis of GC cells, which may be attributable to its direct targeting of BCL2. These results may provide a novel insight into the apoptosis of GC cells, and may lead to investigations into the mechanisms of the effects of TSN.

CircFBXW7 alleviates glioma progression through regulating miR-23a-3p/PTEN axis

Increasing evidence has confirmed that circular RNAs (circRNAs) are involved in regulating the development and progression of various tumors. The aim of this study was to examine the effect of circFBXW7 on the progression of glioma and to determine its underlying mechanism. qRT-PCR was performed to measure the expression of circFBXW7, miR-23a-3p, and PTEN in tissues and cell lines of glioma. The proliferation ability of glioma cells was examined using the CCK-8 assay. Glioma cell migration and invasion capacity were detected using Transwell assays. The dual-luciferase reporter gene assay was employed to examine the correlation between miR-23a-3p and circFBXW7 or PTEN. The expression levels of the related genes were determined using western blotting analysis. A glioma xenograft tumor model was employed to evaluate the functional roles of circFBXW7 in vivo. CircFBXW7 was found to be aberrantly downregulated in glioma tumor tissues and cell lines. Overexpression of circFBXW7 was found to significantly inhibit the proliferation, migration and invasion ability of the glioma cells. Moreover, bioinformatic analysis and dual-luciferase reporter assays confirmed that circFBXW7 can directly target miR-23a-3p, which then blocks the binding of miR-23a-3p to the 3' un-translated region (UTR) of PTEN. Mechanically, circFBXW7 suppresses cell proliferation and metastasis in glioma by sponging miR-23a-3p, resulting in elevated PTEN expression. In addition, in vivo experiments also confirmed that circFBXW7 overexpression effectively halts tumor growth and metastasis. Consistent with the in vitro observations, circFBXW7 overexpression significantly decreased miR-23a-3p, Ki-67, and N-cadherin, as well as increased PTEN and E-cadherin levels. Our results revealed that circFBXW7 exhibits antiproliferative and antimetastasis activities via sponging miR-23a-3p to elevate PTEN expression in glioma, which may offer a novel target for clinical therapy and diagnosis of glioma.

CREB1-induced miR-1204 promoted malignant phenotype of glioblastoma through targeting NR3C2

Background

Glioblastoma (GBM) is a subclass of brain malignancy with unsatisfactory prognosis. MicroRNAs (miRNAs) are a group of non-coding RNAs (ncRNAs) that exert key function on tumorigenesis and tumor development.

Purposes

The purpose of this work was to unravel the biological behavior and mechanism of miR-1204 in GBM.

Methods

Expressions of miR-1204, NR3C2 and CREB1 were detected by RT-qPCR and western blot. Proliferation and apoptosis of GBM cells were detected by CCK-8, colony formation, caspase-3 activity and TUNEL assays. Molecular interplays were examined by ChIP, RIP, and luciferase reporter assays.

Results

MiR-1204 level was elevated in GBM cell lines. Functionally, miR-1204 aggravated cell proliferation whereas suppressed cell apoptosis in GBM cells. Mechanistically, cAMP Responsive Element Binding Protein 1 (CREB1) bound to the promoter of miR-1204 and activated the transcription of miR-1204. Furthermore, miR-1204 targeted and inhibited Nuclear receptor subfamily 3 group C member 2 (NR3C2), a tumor suppressor gene in GBM cells. Rescue assays indicated that NR3C2 participated in the regulation of miR-1204 on the malignant phenotype of GBM cells.

Conclusions

We observed for the first time that CREB1-induced miR-1204 promoted malignant phenotype of GBM through targeting NR3C2, indicating that miR-1204 acted as a novel oncogenic miRNA in GBM.

Focused screening reveals functional effects of microRNAs differentially expressed in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is still a leading cause of death worldwide. Recent studies have pointed to an important role of microRNAs in carcinogenesis. Several microRNAs are described as aberrantly expressed in CRC tissues and in the serum of patients. However, functional outcomes of microRNA aberrant expression still need to be explored at the cellular level. Here, we aimed to investigate the effects of microRNAs aberrantly expressed in CRC samples in the proliferation and cell death of a CRC cell line.

METHODS

We transfected 31 microRNA mimics into HCT116 cells. Total number of live propidium iodide negative (PI-) and dead (PI+) cells were measured 4 days post-transfection by using a high content screening (HCS) approach. HCS was further used to evaluate apoptosis (via Annexin V and PI staining), and to discern between intrinsic and extrinsic apoptotic pathways, by detecting cleaved Caspase 9 and 8, respectively. To reveal mRNA targets and potentially involved mechanisms, we performed microarray gene expression and functional pathway enrichment analysis. Quantitative PCR and western blot were used to validate potential mRNA targets.

RESULTS

Twenty microRNAs altered the proliferation of HCT116 cells in comparison to control. miR-22-3p, miR-24-3p, and miR-101-3p significantly repressed cell proliferation and induced cell death. Interestingly, all anti-proliferative microRNAs in our study had been previously described as poorly expressed in the CRC samples. Predicted miR-101-3p targets that were also downregulated by in our microarray were enriched for genes associated with Wnt and cancer pathways, including MCL-1, a member of the BCL-2 family, involved in apoptosis. Interestingly, miR-101-3p preferentially downregulated the long anti-apoptotic MCL-1 L isoform, and reduced cell survival specifically by activating the intrinsic apoptosis pathway. Moreover, miR-101-3p also downregulated IL6ST, STAT3A/B, and MYC mRNA levels, genes associated with stemness properties of CRC cells.

CONCLUSIONS

microRNAs upregulated in CRC tend to induce proliferation in vitro, whereas microRNAs poorly expressed in CRC halt proliferation and induce cell death. We provide novel evidence linking preferential inhibition of the anti-apoptotic MCL-1 L isoform by miR-101-3p and consequent activation of the intrinsic apoptotic pathway as potential mechanisms for its antitumoral activity, likely due to the inhibition of the IL-6/JAK/STAT signaling pathway.

Molecular Insights into miRNA-Driven Resistance to 5-Fluorouracil and Oxaliplatin Chemotherapy: miR-23b Modulates the Epithelial–Mesenchymal Transition of Colorectal Cancer Cells

Although treatment of colorectal cancer with 5-florouracil and oxaliplatin is widely used, it is frequently followed by a relapse. Therefore, there is an urgent need for profound understanding of chemotherapy resistance mechanisms as well as the profiling of predictive markers for individualized treatment. In this study, we identified the changes in 14 miRNAs in 5-fluouracil and 40 miRNAs in oxaliplatin-resistant cell lines by miRNA sequencing. The decrease in miR-224-5p expression in the 5-fluorouracil-resistant cells correlated with drug insensitivity due to its overexpression-induced drug-dependent apoptosis. On the other hand, the miR-23b/27b/24-1 cluster was overexpressed in oxaliplatin-resistant cells. The knockout of miR-23b led to the partial restoration of oxaliplatin susceptibility, showing the essential role of miR-23b in the development of drug resistance by this cluster. Proteomic analysis identified target genes of miR-23b and showed that endothelial-mesenchymal transition (EMT) was implicated in oxaliplatin insensibility. Data revealed that EMT markers, such as vimentin and SNAI2, were expressed moderately higher in the oxaliplatin-resistant cells and their expression increased further in the less drug-resistant cells, which had miR-23b knockout. This establishes that the balance of EMT contributes to the drug resistance, showing the importance of the miR-23b-mediated fine-tuning of EMT in oxaliplatin-resistant cancer cells.

Diagnostic and prognostic value of microRNA-193b in patients with glioma and its effect on tumor progression

Emerging evidence has indicated the important roles of microRNAs (miRs) in the pathogenesis of cancer in humans. The present study sought to assess the expression patterns of miR-193b in patients with glioma, and investigated its clinical significance and biological function in this disease. The expression of miR-193b in the serum, tissues and cells of patients with glioma was analyzed using reverse transcription-quantitative PCR. Its diagnostic value was evaluated using the receiver operating characteristic (ROC) curve analysis, and its prognostic value was analyzed using Kaplan-Meier survival and Cox regression analyses. Experiments on glioma cells were conducted to explore the influence of miR-193b on proliferation, migration and invasion. Increased expression of miR-193b was observed in serum, tissues and cells of patients with glioma compared with the corresponding controls (all P<0.05). miR-193b expression was associated with the World Health Organization grading and the Karnofsky Performance Scale of the patients (all P<0.05). The area under the curve of the ROC analysis of miR-193b was 0.903, indicating its high diagnostic accuracy for glioma. High expression of miR-193b was associated with poor overall survival rate in patients (P=0.002). Therefore, miR-193b is a potential independent prognostic factor in glioma. Furthermore, the overexpression of this miR in glioma cells led to increased proliferation, migration and invasion, whereas its inhibition resulted in the opposite effects on these cell behaviors (all P<0.05). Thus, the findings from the present study indicate that the overexpression of miR-193b serves as a useful biomarker for the diagnosis and prediction of prognosis in glioma. The upregulation of miR-193b expression may enhance glioma progression, and may therefore be a potential target for glioma therapy.

Plasma microRNA Levels Combined with CEA and CA19-9 in the Follow-Up of Colorectal Cancer Patients

Colorectal cancer (CRC) ranks among the most common cancers worldwide. Surgical removal remains the best strategy for treatment of resectable tumors. An important part of caring for patients after surgery is monitoring for early detection of a possible relapse of the disease. Efforts are being made to improve the sensitivity and specificity of routinely used carcinoembryonic antigen (CEA) with the use of additional biomarkers such as microRNAs. The aim of our study was to evaluate the prognostic potential of microRNAs and their use as markers of disease recurrence. The quantitative estimation of CEA, CA19-9, and 22 selected microRNAs (TaqMan Advanced miRNA Assays) was performed in 85 paired (preoperative and postoperative) blood plasma samples of CRC patients and in samples taken during the follow-up period. We have revealed a statistically significant decrease in plasma levels for miR-20a, miR-23a, miR-210, and miR-223a (p = 0.0093, p = 0.0013, p = 0.0392, and p = 0.0214, respectively) after surgical removal of the tumor tissue. A statistically significant relation to prognosis (overall survival; OS) was recorded for preoperative plasma levels of miR-20a, miR-21, and miR-23a (p = 0.0236, p = 0.0316, and p =0.0271, respectively) in a subgroup of patients who underwent palliative surgery. The best discrimination between patients with favorable and unfavorable outcomes was achieved by a combination of CEA, CA19-9 with miR-21, miR-20a, and miR-23a (p < 0.0001). The use of these microRNAs for early disease recurrence detection was affected by a low specificity in comparison with CEA and CA19-9. CEA and CA19-9 had high specificity but low sensitivity. Our results show the benefit of combining currently used standard biomarkers and microRNAs for precise prognosis estimation.

Interactions among lncRNAs, miRNAs and mRNA in colorectal cancer

Long non-coding RNAs (lncRNAs) are longer than 200 nts non-coding transcripts and have recently emerged as one of the largest and significantly diverse RNA families whereas microRNAs (miRNAs) are highly conserved short single-stranded ncRNAs (∼18-22 nucleotides). As families of small and long evolutionarily conserved ncRNAs, lncRNAs activate and repress genes via a variety of mechanisms at both transcriptional and translational levels, while miRNAs regulate protein-coding gene expression mainly through mRNA degradation or silencing, These ncRNAs have been proved to be involved in multiple biological functions, such as proliferation, differentiation, migration, angiogenesis and apoptosis. Today, while majority of studies have focused on defining the regulatory functions of lncRNAs and miRNAs, limited information have now available for the mutual regulations of lncRNAs, miRNAs and mRNA. Thus, the underlying molecular mechanisms, in particularly the interactions among lncRNAs, miRNAs and mRNA in development, growth, metastasis and therapeutic potential of cancer still remain obscure. Colorectal cancer (CRC) is known as the third most common and fourth leading cancer death worldwide. Increasing evidence showed the close correlations among aberrant expressions of lncRNAs, miRNAs and the occurrence, development of CRC. This review summarize the potential links among these RNAs in following three areas: 1, The biogenesis and roles of miRNAs in CRC; 2, The biogenesis and functions of lncRNAs in CRC; 3, The interactions among lncRNAs, miRNAs and mRNA in tumorigensis, growth, progression, EMT formation, chemoradiotherapy resistance, and therapeutic potential in CRC. We believe that identifying diverging lncRNAs, miRNAs and relevant genes, their interactions and complex molecular regulatory networks will provide important clues for understanding the mechanism and developing novel diagnostic and therapeutic strategies for CRC. Further efforts are warranted to bring the promise of regulating their activities into clinical utilities.